Draft gear



`une 24, 1930.

DRAFT GEAR 2 sheets-sheet 1 Filed Sept. l5, 1923 June 24, 1930.

J. R. cARDwELL ET AL DRAFT GEAR Filed sept. 15, 1923 2 Sheets-Sheet 2 Patented June 24, 1930 UNITED STATES PATENT 'cin-fics;A

JAMES R. CARDWELL AND WALTER COTTON', OFiCIICAG-O, ILLINOIS, ASSllGrNOItSV TO UNION DRAFT GEAR COMPANY, OF CHICAGO, ILLINOIS, A GORPOR-ATIONV OF DELA- WARE DRAFT GEAR i Application filed September 15,/ 19223.V Serial No. 662,845.

The invention relates to draft gears or shock absorbing devices for railway cars; its objects being to secure a high degree of eiiiciency and smoothness of action. The invention consists of a structure such as is hereinafter described, and as'illustrated in the accompanying drawings, in which Fig. 1 is a detail plan View of the under frame of a car, the improved draft gear being shown in central plan section;

Fig. 2 is a sectional view on the line 2--2 of Fig. l;

Fig. 3 is a view similar to Fig. l, the gear being under compression;

Fig. 4 is a sectional view of the gear on the line 1 4 of Fig. 3; and

Fig. 5 is a view in perspective of one of the wedging shoes of the gear.

A pair of center or draft sills of a railway car is shown at 10, 10, each being provided with a draft lug 11, 11, and a buiiing lug 12, 12. The draw-bar of a coupling device is shown at 13, and its extension, shown in th'e form of a yoke or loop for encircling the draft gear, is represented at 14.

The improved gear comprises a front and a rear follower, designated, respectively, 16,17, each being in box form and comprising an end plate for engaging the draft or bufling lugs, and side, top and bottom walls, these walls being of such length that those of the one follower meet those of the other follower when the gear is fully compressed, thereby preventing over-compression and a consequent injury of the springs.

The end plate of each of the followers is centrally recessed to accommodate the head and nut of a retaining bolt 18, which serves to hold the various elements of the gear in assembled relation pending installation upon a car.

l/Vedge-blocks 19, 20, are seated against the inner faces of the end plates of the two followers, as shown, the bearing being in each case upon the boss formed inv recessing these plates as hereinbefore described. Two pairs of wedging shoes 21,22, and 23, 24, are provided, one pair being associated with each of the wedge-blocks 19, 20. These shoes mayH be identical in form, one thereof being shown in Fig. 5. f

A helical spring 25 reacts between the two pairs of'wedging shoes, a spring seat, as 26, being preferably interposed between each end of the spring and the shoes associated therewith, and the engaging .faces of the spring" seats and the slices are preferably inclined with reference to the axis of the gear, and at a more obtuse angle thereto, than are the wedging faces of the shoes which engage the wedge-blocks 19, 20. i

The base of each of the wedging shoes is prolonged, as shown at 27,2721, to provide a somewhat extended friction surface.

Wedging friction shoes 28, 29, are seated one against each of the side walls of the two followers 16, 17, their lengthbeing preferably slightly less than the distance between the end plates of the two followers when the gear is fully compressed, as shown in Fig. 3. The wedging faces of the shoes 28 and 29 are at their outer sides, and bear `against correspondingly inclined side walls of the fol-` lowers.` These wedging faces are of considerable length and are inclined at quite an acute angle to the axis of the gear.

Interposed between each of the friction shoes 28, 29, and the adjacent wedging shoes 21, 23, in the one case, and 22, 24, in the other, are two sets of friction plates 30, 31, the width of the plates of each set being slightly less than one-half of the internal height of the follower. The length of the plates of each of the sets is slightly less than the distance between the innerV faces of the end plates of the followers when the gear is fully compressed, as in Fig. 3.

Alternate plates of eachset normally extend from a short distance from the end plate of the forward follower 16 and the remaining plates of the same set from a short distance from the end plate of the rearward follower 17. Plates of the two sets which occupy the same vertical plane cooperate with different followers. That is to say, considering the two plates in full view in Fig. 2, the upper one cooperates with the forward follower 16 and the lower one with the rearward follower 17.

A helical releasing spring 32 reacts directly between the wedge blocks 19, 20, and is inclosed within the spring 25.

When the gear is compressed either in draft or buff one of the followers remains at rest against either the draft lugs or the bufng lugs, the other follower being moved toward it. This movement is resisted by both of the springs. The advance of the wedge-block associated with the follower which is in motion tends to carry with it the wedge shoes with which it is associated,- this movement, however, being resisted by the spring causes lateral movement of the shoes.` The advancing pressure being communicated through the spring 25 to the wedging shoes at the opposite end of the gear, they are caused to move outwardly on the faces of the wedge-block with which they cooperate.

The advancing follower slides upon the friction shoes 2S, 29, forcing them inwardly and also causing them to advance with a wedging action upon the stationary follower. The outward movement of the wedging shoes 21 to 211, and the inward movement of the friction shoes 28, 29, put the plates and 31 under strong compression, forcing the shoes 21 to 24 inwardly and causing them to advance with reference to the wedge blocks 19, 20. The moving follower comes into engagement with the ends of the friction plates of the several sets which are adjacent to it and carries these plates forward between the plates with which they are intercalated, on moving the latter into engagement with the stationary follower.

The continued movement of the follower is resisted not only by the springs, but by the friction developed between the contacting faces of relatively movable parts of the gear, and this resistance increases until the gear has been fully compressed.

Upon release the spring 32 moves back the follower which had been advance-d, relieving the wedging action upon the wedging shoes and the friction wedge plates 28, 29,-a too sudden release being prevented by the eXpan- .sion of the spring 25, whichleeps the wedging shoes in contact with the wedge-blocks. To insure the return of the friction plates to normal position each of the wedge-blocks 21 to 24 is provided with an outwardly projectlng lug 33, which enters within a recess, as shown at 34, formed in the inner margin of the plates-'30, 31, near the end thereof WlCll is adjacent one of the follower plates. At the opposite end of the friction plates a section is cut out, as indicated at 35, to provide clearance for the lug 33 for controlling the other set of plates.

By the use of friction plates the width of which is but half the height of the gear, and arranging the plates of the two sets in reverse order as shown, the tendency of one of the plates contacting with the shoes as 24; and with the wedging shoes 29, to carry these members along with them is counteracted by the other plates in engagement with the same members, which move relatively in the opposite direction.

YWhile a preferred and highly efficient form of construction is shown and described, various changes of detail may be made without departing from the scope of the invention, and some of the features of improvement may be incorporated in gears which are differently organized.

We claim as our invention- 1. In a draft gear, in combination, a pair of chambered followers having friction surfaces, a set of central wedging elements in each follower, intercalating plates interposed between the two sets of such elements and said friction surfaces, the plates at each side comprising upper and lower groups, the sets of plates of the two groups at each side being arranged in reverse order, and means for yieldingly resisting the compression of said gear.

2. In a draft gear, in combination, a pair of chambered followers, groups of intercalating plates within the followers, wedging elements in each follower and interposed between groups of the plates, such elements comprising Ashoes each frictionally engaging contiguou-s plates,such shoes being provided with integral retracting lugs having a loose motion connection with shoulders on a plurality of the plates, means for yieldingly resisting the inward movement of said elements, and means for retracting the shoes after the compression of the gear.

3. In a draft gear, in combination, a pair of chambered followers havino' friction surfaces on their side walls, a set of central wedging elements within each follower, each set comprising a pair of friction shoes, groups of upper and lower intercalating friction plates interposed between the shoes at each side of the gear, the shoes being provided with integral lugs projecting between the upper and lower groups of plates and engagable with shoulders on the plates of one set of each group, and means for yieldingly resisting compression of said gear.

4. In4 a friction shock absorbing mechanism, the combination with front and rear follower members; of a plurality of longitudinally disposed, friction plates interposed between said followers, said plates being alternated and divided into two separated groups; means enclosing said groups of plates for resisting lateral outward movement thereof; lateral pressure-Creating means at each end of the mechanism, said means vincluding friction Wedge shoes (5o-operating with the two groups of friction plates, said shoes having lugs thereon for restoring the plates to normal position; and spring resistance means for said lateral pressure means.

JAMES R. GARDl/VELL.

WALTER H. COTTON. 

